Neutron-diffraction and Mössbauer-effect studies of Pr2(Fe1−xMnx)14B

Abstract

A neutron-diffraction investigation of a series of Pr2(Fe1−xMnx)14B samples, with x values of 0.00, 0.11, 0.22, 0.30, and 0.35, reveals a preference for the manganese to occupy the 8j2 transition-metal site,the transition-metal site with the largest Wigner–Seitz cell volume. Similar site occupancies have been reported previously for Er2(Fe1−xMnx)14B and Y2(Fe1−xMnx)14B. An analysis of the 295-K Mössbauer spectrum of Pr2(Fe0.89Mn0.11)14B indicates that the internal hyperfine fields on the six iron sites are more substantially reduced from those found in Pr2Fe14B than would be expected from a simple magnetic dilution with manganese. The extent of the field reduction for a specific site increases with the number of manganese near neighbors for the site. Fits of the Mössbauer spectra of Pr2(Fe0.78Mn0.22)14B, Pr2(Fe0.70Mn0.30)14B, and Pr2(Fe0.65Mn0.35)14B, which are paramagnetic at room temperature, give quadrupole splittings consistent with the quadrupole interactions in Pr2Fe14B.